Watching the hills emerging so suddenly from the perfect flatness of the Sink in the smoky air, Armen and Sam each felt a sensation of wonder in coming so close to something rising so unnaturally out of their flat universe. The hills, some quite rocky, jutted suddenly out of the level soil of the Sink. Mountain ranges more commonly taper down slowly into rolling plains, but these mountains seemed to have sunk into a giant vat of silt, an instant transition from mountain to utter flatness. The topographical transition seemed so sudden that each submerged mountaintop seemed like a barnacle-encrusted whale breaching in a sea of orange groves.
Barnacled whales east of Cutler, California
It is not just these few mountains and hills that are sounding like whales into the sea of soil under the Sink. Much of the surrounding mountains are also subsiding, though it is not so easy to recognize because those mountains are still far above the Sink. They’re on their way down, though, and they too will dive into the silt sea when their time arrives.
Likewise, the bedrock under the Sink is subsiding, as evidenced by the depression at its heart where the waters of Tulare Lake once collected. The primary factor that keeps towns such as Slough City from subsiding into a monstrous pit is the persistent supply of silt provided by the streams flowing off of the Range.
The Sink is more than just a basin that happens to be adjacent to a mountain range. The Sink and the Range have formed together. This is true of the Range and the Great Valley as a whole, but more so for the Sink, which deepens a little every year to receive that much more of the erosional tailings of the Range. The Sink is a kind of massive sinkhole born some twenty million years ago, when a great sliding door under California opened to the underworld. But this sinkhole opens slowly, so the streams, loaded with the rich erosional product of a rapidly rising monolith, have no problem keeping the pit filled.